Process of producing carbids.



No. 6903). Patented Dec. 3|, I90l.

I. L. ROBERTS.

noczss 0F PRODUCING CARBIDS. I A ummmed Apr. 6.1896.) (No Model.) I 2Sheets-Sheet I.

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' UNITED STATES,

PATENT FFICE.

ISAIAH L. RoBERTs, or BROOKLYN, NEW YORK.

1 PROCESS OF PRODUCING oA'RBms.

srnorrroAcrron forming part of Letters Patent no. 690,319, datedDecember 31, 1901. Application filedApril 6,1896. Serial No. 586,314.(No specimens.)

To all whom it may concern:

Be it known that I, ISAIAH L. ROBERTS, of the city of Brooklyn,countyjof Kings, and State of NewYork, have invented a new and usefulImprovement in Processes for the Production of Carbide, of'which thefollowing is a full, true, and exact description, ref

erence being had to the accompanying drawings.

My invention relates to a process for the production of carbids.

I will describe a processembodying my in vention and then point out thenovel features in the claims.

Inthe drawings, Figure 1 is a vertical section through a furnaceembodying my invention. Fig. 2 is a vertical elevation of the electrodeshown in Fig. 1; and Fig. 3 is a modification of the furnace shown inFig. 1, the operating parts being entirely confined within the furnace.

Similar letters of reference refer to corresponding parts.

A is the brickwork, and B and O are the electrodes.

D represents mixtures of carbon and oxid.

E represents carbids, and F represents gate-valves. i

In constructing thefurnace I use fire-brick or magnesia for the innerportion, and in the form shown in Fig. 3 I also build in a tube 1) inthe top for the escape of any gases evolved in working the furnace; Aflanged pipe L is also built in the lower opening of the furnace andfurnished with agate-valve F.

The process of making carbids in this furnace is as follows: I make amixture of the oxid and carbon by grinding them together in properproportion, which is fed to the electrodes. The electrodes are thenpushed together until they meet and touch. A current of electricity isthen turned on, gently at first, as there is comparatively-littleresistance in the furnace when the electrodes are touching. When thecurrent is passing, the electrodes are slightly drawn apart and an .arcis formed. Then the current is increased sufficiently to heat the entireends of the electrodes to a'white heat.

When this is done, the oxid and carbon will become hot enough to be aconductor of electricity, and then by are and incandescence it willbecome so hot that it will become carbid'of what- 'ever metal is usedwhich is capable of being made into a carbid and will fuse'and drop downby gravity into the space E. I

I prefer to use a mixture of unslaked lime and carbon ground together inthe proper proportions to form the carbid, andfor use in the furnacedescribed in Fig. 3 I press the mixture into bricks or cylinders by bydraulic pressure into molds. In order to make them sure of holdingtogether, I mix in some binding material-such as bitumen, pitch,or

sugar syrup-when grinding the lime and carbon, and thus grind the wholetogether. When pressing, I prefer to heat the mixture tothemelting-point of the binder. -Th'e reason I prefer unslaked lime inall my furnaces is that it occupies less space and saves that heatnecessary to drive off the water which is in slaked lime, thusconcentrating. the current on a greater quantity of material in a givenspace, which is impossible with slacked lime.

When the carbid is formed at the point of contact or are, it drops awayby gravity, as

at that time itbecomes more'or less liquid and is caught on thegate-valve F. When the space between the said gate-valve and the arcgets too full, the valveis opened, and it is allowed to drop into areceptacle G, if desired.

In this case the receptacle should fit tightly on'the lower end of thetube at L, and the said receptacle must be filled with some gascontaining little or no oxygen after the said receptacle is placed inposition by displacement, as may be done by allowing the carbouic-oxidgas made in the production of carbid by the decomposition of its lime oroxid in making it and which escapes through the tube'b and which may beled into the receptacle after being fastened to the cylinder L beforethe gate-valve F is opened. When the receptacle is filled or when theamount of accumulated carbid on the gate-valve is removed, it may beagain. closed and the receptacle removed, thus repeating as often asdesired.

The electrodes B andC are fiat, and the furnace of Fig. 1 is in V shapeat its top. These electrodes articulate at N N on pins, so that theirlower ends may be moved together, forming an angle, by the use of thetoo' screws P P, and on reversing the screws grav ily will cause them torecede from each other, thus regulating the space between them asdesired.

In order to make carbids in this furnace, I make a mixture of the oxidand carbon in a I loose form and place it between the electrodes,

as shown at D. To operate this furnace, I move the electrodes togetherat their lower ends by use of the screws P P and fill in the spacebetween them with a loose mixture of carbon and oxid. I next turn on thecurrent, gently at first, through the electrodes while in contact attheir lower ends and establish a circuit and then separate themslightly, which will establish an arc. I then increase the current tosuch a degree as will bring the ends of the carbon to a high heat. Theoxids and carbon in proximity to the arc will become very highly heated,and thus become a conductor of electricity, and will become so heated asto form the carbid, which will fuse and run through the space betweenthe ends into the space above the gate-valve F and accumulate at E, andthus the furnace will antomatically regulate its own feed, and thecarbid will automatically displace itself from the are as fast asformed, while little or no oxid and carbon can escape unconverted intocarbid.

Another form of furnace is shown in Fig. 3, wherein the oXid and limeare fed into the angle made by the two electrodes 1) O by gravitation inthe form of a-brick or stick D and are converted into carbid byincandescence and the are combined. These bricks or sticks are joined attheir ends by a small amount of ends of the electrodes are very hot.

asphalt or bitumen, which the heat of the furnace carbonizes as itadvances and makes solid. On starting this furnace the current isstarted gently and increased as the carbons areallowed to fall apart bymoving the screws P P until a strong arc is established and the Thebricks of oxid and carbon are fed in gently becomes so hot at the end ofthe brick or point I of contact that it becomes a conductor ofelectricity and takes the current by incan descence and are, accordingto whether it is a good or bad contact, and is heated to the point offusion as carbid and drops down on the gate-valve F and is removed, asdescribed in the other figures. This furnace has a movable cover at O 0,so that new electrodes can be put in when the old ones are worn tooshort 1. The rocess of makin calcium carbid which consists in feeding amass of carbon and calcium oxid solely by gravity to a pair ofangularly-disposed electrodes, passing a current of low amperage throughthe mass and then increasing the amperage of the current independentlyof the variable resistance due to the supply and discharge of the material thereby freeing the mass and effecting its gravitation.

2. The. process of making calcium carbid which consists in feeding abrick or block of carbon and calcium oxid into the space between a pairof angularly-disposed electrodes and in applying an electric currentfirst of gentle strength and subsequently of high intensity.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ISAIAH L. ROBERTS.

Witnesses:

H. COUTANT, ERNEST ,HOPKINSON.

